GPS (global positioning system) antennas or other antennas for communication of a moving body such as an artificial satellite must have a property of clockwise circular polarization. Although there are various possible methods for obtaining such an antenna, it is very difficult to establish both a hemispherical or isotropic directivity and a circular polarization characteristic. In this situation, a conventional practical solution was array-arrangement of dipole, loop or other planar radiating elements, or alternatively the use of spiral tridimensional radiating elements.
These prior art antenna arrangements certainly enabled realization of an antenna substantially satisfying to a certain degree the aforementioned characteristics. However, it requires much experience and know-how. Besides this, the prior art antennas involve a certain compromise between the aforementioned characteristics, and various disadvantages, i.e. large scale and complicated structure of the entire antenna, difficult handling and cost increase.